Americans are celebrating the Labor Day weekend, culminating in the Monday holiday honoring U.S. workers and their contributions to the country's economy.

The holiday has also come to signal the unofficial end of summer in the United States. Most workers have the holiday off and often celebrate over the weekend with family picnics and vacations. In some communities, Labor Day is the last day before the school year starts for students.

Many people on the East Coast may see their holiday plans dampened by Hurricane Hermine, which crossed into Florida from the Gulf of Mexico on Friday and began moving into Georgia and the Carolinas.

The storm has caused weather alerts and precautionary closures along much of the Atlantic Coast, including in New York City where Mayor Bill de Blasio said city beaches will be closed for swimming Sunday — and possibly through Tuesday — because of potentially dangerous riptides.

"The number one thing I want to say New Yorkers is: The riptides are extremely dangerous. This is my number one message," he said.

Labor Day in the U.S., held the first Monday in September, became an official holiday in 1894 after a push by the nation's labor unions. For decades, cities used the occasion to stage large parades honoring unionized factory workers.

Labor unions have seen their membership fall steadily in the past 30 years with the growth of technology and the globalization of the world economy. However, workers' benefits —which the unions fought for decades ago — are now customary in most U.S. workplaces, including five-day work weeks, health care insurance and vacations paid for by employers.

Many union members now work for local, state and federal governments in white-collar jobs, not in the gritty factories where the labor movement began.